bakaneko (no@spam.org) on 6/24/11 wrote:

>What about heat pipes? They do basically the same, but without forcing
>you to use a complex system to control the fluid, are a closed system
>and can be used with passive cooling.

Agreed: they are better than water and they all those advantages you've enumerated.

Can they provide better cooling than water?
Considering currently available products, water based radiators still seem to have the upper hand.

Here a couple of images to illustrate my point.

Heat pipe based radiator for a CPU: http://pcper.com/images/reviews/139/XP-90c6.jpg

Water radiator, about 130x130 mm: http://www.overclockers.co.nz/product/watercool/GTS-120BL-B.jpg

The heat pipe design has 4 pipes bringing the heat to the ends of the fins but it still relies quite a bit on heat spreading across the fins into the middle.

The water radiator, on the other hand, has 12 pipes to distribute heat to the fins and relies much less on heat spreading. It also has a much higher fin density.

Now, can heat pipe radiators improve to overcome water based radiators?
I don't know squat about heat pipe design, so I don't know.